This affects more than comments. In a brand new installation of 1.5, I received the first e-mail with my administrative password, but then trying to register as a new user I did not get the confirmation messages with the password for the new accounts. Deleting “$more” fixed that as well.
And my “from” address was incorrect too, I’ll have to try the suggestion above. It seems the administrative e-mail address on the “options” page is simply ignored.